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LITTLE FALLS, N.J., April 20 -- Specialized regional networks provided the vast majority of patients with acute ST-elevation myocardial infarction (STEMI) with reperfusion times within guideline recommendations, researchers found.

In a pooled analysis of 10 networks throughout the U.S., 86% of STEMI patients had a door-to-balloon time of 90 minutes or less, according to Ivan Rokos, M.D., of the University of California Los Angeles-Olive View Medical Center in Sylmar, Calif., and colleagues.

A key component of each network was the early identification of ST-elevation by paramedics, the researchers reported in the April issue of the Journal of the American College of Cardiology: Cardiovascular Interventions.

"For decades, paramedics, emergency departments, and cardiology teams have coexisted, but we have only recently recognized how important it is to coordinate all three into one seamless unit that delivers rapid primary percutaneous coronary intervention and restores blood flow in a blocked coronary," Dr. Rokos said.

"As this study shows," he said, "paramedics can diagnose STEMI heart attacks quickly and can trigger the activation of an entire system, which allows patients to enter a virtual express lane to the cath lab team at the nearest STEMI hospital."

The analysis included 10 STEMI networks -- five in California and one each in Oregon, Minnesota, Michigan, North Carolina, and Georgia -- encompassing 72 hospitals.

Each network was characterized by universal access to 911, prehospital diagnosis of ST-elevation by paramedics using electrocardiograms, early activation of a team at the nearest cath lab, and the permitted bypassing of hospitals that didn't have a cath lab.

In a network in Atlanta, the ECG results were transmitted wirelessly in advance to the hospital.

During the study period, 2,712 STEMI patients were treated through August 2007.

Primary PCI was performed in 76%. It was unclear why the other 24% did not undergo PCI, the researchers said.

Of those who had an intervention, 86% had a door-to-balloon time of 90 minutes of less.

This rate compares favorably with a 40% rate in a registry study conducted from 1999 through 2002.

Each network exceeded the standard of the American College of Cardiology Door-to-Balloon (D2B) Alliance -- an initiative launched in 2006, which set a target of more than 75% of patients receiving PCI in 90 minutes or less upon arrival at the hospital.

The rate ranged from 77% in Atlanta to 97% in Minneapolis.

In a secondary analysis, the researchers found that 50% of patients had a door-to-balloon time of one hour or less, 25% had one of 45 minutes or less, and 8% were in the cath lab in 30 minutes or less.

In addition, 68% had a time from first ECG in the ambulance to reperfusion of 90 minutes or less.

"These results are . . . consistent with the most recent guidelines, which strongly endorse a continued focus on faster reperfusion times, better systems of care, and an expanded use of the prehospital ECG," the researchers said.

Dr. Rooks noted that inappropriate cath lab activation could occur because of the prehospital diagnosis of ST-elevation, but that the false-positive rate could not be determined from this analysis.

Other limitations included the lack of information on clinical outcomes and conventional experimental study variables, as well as potential bias in the selection of networks included.

In an accompanying editorial, Christopher Granger, M.D., of Duke University Medical Center said, "It can no longer be argued that it is impossible to establish an integrated EMS and hospital system to provide faster primary PCI."

"The most important lesson of this study," he continued, "is that reperfusion with primary PCI can be provided more rapidly if EMS is placed in its rightful position as the front line for integrated STEMI care. Expansion of what these 10 networks have done on a national scale -- refined and coupled with better EMS support, data collection, and feedback -- will improve care and save lives."

The study authors made no financial disclosures. Dr. Granger receives funding support and/or honoraria from Blue Cross Blue Shield of North Carolina, Genentech, sanofi-aventis, Bristol-Myers Squibb, The Medicines Company, and Novartis.

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